A web server usable for providing web hosting services may involve a physical server machine and a Network Interface Device (NID). The NID may take the form of an expansion card that is coupled to the motherboard of the physical server machine via a PCIe bus. The NID provides internet and network connectivity to the server machine. The resources of the server machine may be partitioned and allocated by a hypervisor so that multiple separate virtual machines can operate simultaneously on the same one physical server machine without interacting with each other. Similarly, the resources of the NID may be partitioned and allocated so that the NID functions as multiple virtual NIDs. The single physical server machine can therefore function as multiple separate virtual servers, with each separate virtual server involving a virtual machine and an associated virtual NID. In the web hosting business, a company that owns such a physical server can lease use of individual virtual servers and internet connectivity to individual customers. An individual customer may of the web hosting company may, for example, use such a leased virtual server to host the customer's website even though the actual physical server hardware being used is owned by the web hosting company and is also being used by many other website operators. There are many different architectures that can be employed to realize NIDs for web servers. In one example, a high-performance and intelligent Island-Based Network Flow Processor (IB-NFP) available from Netronome Systems Inc. of Santa Clara, Calif. is employed. Ways of optimizing system performance without unduly increasing manufacturing costs are sought.